Preparation Of Chlorinated Polyvinyl Chloride(CPVC) Composite Nanofiltration Membrane And Its Application In Simulated Reactive Black 5(RB5) Dye Wastewater Treatment

At present,dye wastewater is not only large in quantity,but also has stable chemical properties and strong toxicity.It is very harmful to humans and the environment,and it is difficult to use conventional treatment methods to be effective.Nanofiltration membrane separation technology provides a bright future for the effective treatment of dye wastewater.The core component of nanofiltration membrane separation technology is nanofiltration membrane materials.Therefore,the key to the development of nanofiltration membrane separation technology is to develop new nanofiltration membrane materials.In this paper,CPVC composite nanofiltration membrane was prepared using chlorinated polyvinyl chloride（CPVC）ultrafiltration membrane as the base membrane.The effects of tannic acid（TA）/piperazine（PIP）and Gallic acid（GA）/PIP on the performance of CPVC composite nanofiltration membrane were investigated.At the same time,the effects of preparation conditions,drying time,the ratio of TA/PIP,the ratio of GA/PIP,the concentration of co-sediment and the concentration of TMC,the cross-linking agent,on the performance of CPVC composite nanofiltration membrane were discussed.On this basis,the treatment effect and operation stability of CPVC composite nanofiltration membrane prepared by two different co-deposition systems for simulated RB5 dye wastewater were investigated.Through the research,the following conclusions are drawn:（1）With the increase of drying time,the PA/TA/CPVC composite nanofiltration membrane tends to stabilize after increasing the pure water flux,and the rejection rate increases slightly;with the increase of the TA/PIP concentration ratio,the pure water flux When the total concentration of TA+PIP increases,the pure water flux decreases and the interception rate gradually increases;as the TMC concentration increases,the pure water flux decreases first and then increases.It first decreases and then increases,and the interception rate gradually increases and then slightly decreases.When the drying time is 20min,the concentration ratio of TA/PIP is 7/3,the total concentration of TA+PIP is 0.5g/L,and the concentration of TMC is 1.0g/L,the prepared PA/TA/CPVC composite nanofiltration membrane has the best Good performance.The pure water flux of the composite nanofiltration membrane prepared under the optimal conditions is4.5LMH·bar^-1,and the rejection rate of PEG1000 is 95.8%.（2）As the drying time increases,the pure water flux of the PA/GA/CPVC composite nanofiltration membrane gradually increases,and the rejection rate decreases after a slight increase;with the increase of the GA/PIP concentration ratio,the pure water flux Keep increasing,the interception rate gradually decreases;as the total concentration of GA+PIP increases,the pure water flux decreases,and the interception rate gradually increases;as the TMC concentration increases,the pure water flux first decreases and then increases,The interception rate is gradually increasing.When the drying time is20min,the GA/PIP concentration ratio is 5/5,the total GA+PIP concentration is 0.5g/L,and the TMC concentration is 1.0g/L,the prepared PA/GA/CPVC composite nanofiltration membrane has the best Good performance.Under the optimal conditions,the pure water flux of the composite nanofiltration membrane was 3.3LMH·bar^-1,and the rejection rate for PEG1000 was 93.4%.（3）When treating simulated RB5 dye wastewater,the PA/TA/CPVC composite nanofiltration membrane increases with the increase of drying time,and the dye flux first increases,reaches the maximum at 20 minutes,and then stabilizes.The rejection rate of RB5 dye as the concentration ratio of TA/PIP increases,the dye flux first increases and then decreases slightly,and the dye rejection rate of RB5 dye first decreases and then increases;as the total concentration of TA+PIP increases,The dye flux gradually decreases,and the dye rejection rate gradually increases;with the increase of TMC concentration,the dye flux first decreases and then increases,and the dye rejection rate first increases and then decreases.When the simulated RB5 dye wastewater was continuously treated for 6 hours,the dye wastewater flux remained stable overall.With the increase of drying time,the dye flux of PA/GA/CPVC composite nanofiltration membrane gradually increased,and the rejection rate of RB5 dye increased slightly and then gradually decreased;with the increase of the GA/PIP concentration ratio,the dye wastewater flux When the total concentration of GA+PIP increases all the time,the dye rejection rate gradually decreases;as the total concentration of GA+PIP increases,the dye flux gradually decreases,and the dye rejection rate gradually increases;as the TMC concentration increases,the dye flux first decreases and then increases,and the dye rejection takes the lead Increase and decrease.When the simulated RB5 dye wastewater was continuously treated for 6 hours,the dye wastewater flux remained stable overall.